Water Gardening: Strange plant in container water garden, 1 by revclaus

revclaus wrote:
I've never had this happen in the five or six years I've been planting a container water garden. I hope somebody can help me identify this totally rampant grower in my water garden. I took out a lot of it a couple of weeks ago, but it just multiplied like Topsy. I had a water lily planted in the container, but this stuff has obscured anything but itself. When I first planted the garden I put a handful of duckweed in it which was doing fine until it got run over by this stuff. Any ideas about what it is and what I can do about it?